Linseed oil is a colorless to yellow color oil extracted from flax seeds. Only dried and ripened seeds of the flax plant (Linum usitatissimum) are used for obtaining linseed oil, also called as flaxseed oil or flax oil. Pressing is the processing technique to obtain this oil, sometimes followed by solvent extraction. This edible oil is a rich source of α-Linolenic acid, (an omega-3 fatty acid), and therefore is highly demanded as a nutritional supplement.
There are many uses of linseed oil. It used as a preservative to preserve concrete and wood, and as an ingredient in products, such as ink, paint, varnish, stain and soap. It can also be added to mineral turpentine to enable penetration and quicken the drying process.
The oil is also used as an important ingredient in oleoresinous printing ink varnishes, where it is reacted with one or more resins and then let down in a high boiling point solvent. Its refined version finds use in heat set and cold set printing inks as an additive.